The study of the voice function begins already during a conversation with the patient when assessing the timbre of voice and sound paraphenomena that occur when breathing and voice functions are disturbed. Afonium or dysphonia, stridorous or noisy breathing, distorted timbre of voice and other phenomena can indicate the nature of the pathological process.
With volumetric processes of the larynx, the voice is squashed, muffled, its individual timbre is lost, often the conversation is interrupted by a slow deep inspiration. With a "fresh" paralysis of the narrowing of the voice gap, the voice loses its sonority, a large amount of air is expended through the gaping voice slot for pronouncing the word, so the patient does not have enough air in the lungs to pronounce the whole phrase, because of which his speech is interrupted by frequent breaths, the phrase is fragmented by Separate words and during a conversation there is hyperventilation of the lungs with respiratory pauses.
With chronic dysfunction of the vocal folds, when the compensation of the voice function arises due to folds of the vestibule, the voice becomes coarse, low, hoarse. If there is a polyp, fibroma or papilloma on the voice fold, the voice becomes a cracked, rattling sound with additional sounds, arising from the vibration of the formation on the voice fold. Stenosis of the larynx is recognized by the stridorous sound that occurs during inspiration.
Study of the laryngeal function
Vibrometry is one of the most effective methods for studying the voice function of the larynx. Accelerometers are used for this purpose, in particular, the so-called maximum accelerometer, which measures the moment when the vibrating body reaches a given frequency of sound or maximum acceleration in the range of the background frequencies, that is, the vibration parameters. Assess the condition and dynamics of these parameters both in the norm and under various pathological conditions.
Rheography of the larynx (glotography)
The method is based on recording changes in the ohmic resistance to an electric current that occur when the vocal folds converge and divide, as well as with changes in their volume during phonation. Changes in the resistance to electric current occur synchronously with the phantom vibration of the vocal folds and are registered as oscillations (rheograms) with the help of a special electrical device - the rheograph. The shape of the rheolaryngogram reflects the state of the motor function of the vocal folds. With quiet breathing (without phonation), the rheogram is represented as a straight line, slightly undulating in time to the respiratory excursions of the vocal folds. During phonation, oscillations appear that are close in shape to the sinusoid, whose amplitude correlates with the loudness of the sound produced, and the frequency is equal to the frequency of this sound. Normally, the parameters of the glotogram are characterized by high regularity (constancy). With violations of the motor (flash) function, these violations in the records are displayed in the form of characteristic changes characteristic of organic and functional disorders. Often a glotography is carried out simultaneously with the recording of a phonogram. Such a study is called phonoglottography.
Stroboscopy of the larynx is one of the most important methods of functional research, allowing visualization of the movements of the vocal folds at a different frequency of stroboscopic effect. This allows you to visualize the movements of the vocal folds during phonation in slow motion or even "stop" them in a certain breeding or information state.
Stroboscopy of the larynx is carried out with the help of special devices called stroboscopes. Modern stroboscopes are divided into mechanical or optical-mechanical, electronic and oscillographic. In medical practice, video-stroboscopic devices with wide multifunctional capabilities became widespread.
With pathological conditions of the vocal apparatus, various stroboscopic pictures can be observed. When assessing these pictures, it is necessary to take into account visually the level of the position of the vocal folds, the synchrony and symmetry (mirroring) of their oscillations, the nature of their interlocking, and the auscultatory timbre of the voice. Modern video stroboscopes allow simultaneous recording in the dynamics of the stroboscopic picture of the larynx, the amplitude-frequency characteristics of the phonetic sound, the phonogram of the voice, and then perform a correlation analysis between the recorded parameters and the video-stroboscopic image.
Laryngeal stroboscopy image of vocal folds at normal phonation:
- The phase of closing the vocal folds
- The phase of opening the vocal folds